Manufacture of cement.



PATENT OFFICE.

ANDRE HEIIBBONINTEB, 0F PARIS, FRANCE.

MANUFACTURE OF CEMENT.

No Drawing.

To all whom it may concern:

Be it known that I, ANDRE Hnnnnonnan, a citizen of the French Republic, residing at Paris, France, have invented a new and use ful Improvement in the Manufacture of Cement, of which the following is a specification.

This invention relates to the manufacture of a white or nearly white cement. The cement is made from raw materials which contain substances which in the usual manufacture of cement would discolor the product and greatly reduce its salable value.

Generallly in white cement manufacture it has been found necessary to use kaolins and other clays which are free of oxid of iron. If oxid of iron is present, the resulting cement is gray in color and is of much less value than if white. In white cement manufacture, mixtures of kaolin, calcareous material are mixed with suitable fluxes such as feldspar or boracic acid and submitted to the influence of heat. Generally the fuel for producing the heat must be kept from contact with the materials since the fuel itselfdcontains considerable quantities of iron 0x1 In this improved process the fuel can be mixed directly with the mixture since it is possible to use common clays containing iron oxide in considerable quantities. oxid in the fuel merely adds to the iron oxid in the clay and is converted into other substances which do not discolor the resulting product.

In my improved process I add to the raw materials employed (bricks, calcareous clay, slag, etc.) a certain amount of calcium chlorid. The exact amount of calcium chlorid added depends upon the weight of iron oxid present in the raw material and the fuel but it is preferabl that the weight of calcium chlorid used, be slightly in excess of the weight of iron oxid present in the mixture. The mixture is then submittedat high temperatures to the action of steam. When this is done it will be found that the reversion'ary reaction of nascent hydrochloric acid formed by combination of the calcium chlorid and steam takes place in such direction that the iron cxid. is acted up n nd.

Specification of Letters Patent.

The iron Patented Sept. 11, 1917.

Application filed December 29, 1913. Serial No. 809,224.

the deleterious colored iron oxide.

As an illustration of this process I have utilized a mixture of 4: parts of clay, 15 parts of calcium carbonate,

1 part of calcium chlorid.-

This mixture is then submitted at high temperature to the action of superheated steam. If so desired coal may be added directly to the mixture. This renders the material more porous as the coal is consumed and any oxid of iron in the ashes of the coal is converted into the volatile chlorids and driven from the mixture. The coal in the mixture also supplies a certain amount of heat which aids the reaction.

As. calcium chlorid is a comparatively valueless industrial residue its utilization in the manufacture of the much sought white cement provides an additional use for this comparatively worthless substance. It will be understood, however, that other earth chlorids may beutilized as well, for example, barium or magnesium chlorid.

Another of the well known kilns may be utilized in the carrying out of this process. If desired. thewell known vertical kilns may 1 be used. In usual cement manufacture clay and calcareous material are first dried, then mixed and finally kneaded with about 25-35% of water. With the present process the water may be replaced with a solution of calcium chlorid. After mixing, the paste and the fuel is arranged in successive layers in the kiln and fired or if desired the clay, calcare us material, calcium chlorid solution and fue are all mixed into an agglomerate mass and placed in the kiln. This method is advantageous in that it permits a closer intermixture of the nascent hydrochloric acid and the mixture and a resulting better conversion of the iron oxid into iron chlorid.

In practice the steam-is admitted into the lower part ofthe kiln throu h one or more blast pipes which also supp y air andgaseous fuel as is Well known in cement manuwhere it is desired to facture. Or if desired the steam may be admitted through a central pipe. It is desirable that the steam in passing through the mixture be in a superheated condition. The superheated steam Will readily penetrate the material and carry out the reaction described even if the material is in the form of bricks.

Another way of carrying out the process consists in blowing into the kiln by means of an injector a mixture of clay, lime, coal, calcium chlorid, steam and air.

It is important in carrying out this process that the steam and air be carefully proportioned so that the hydrochloric acid evolved will be sufficiently concentrated to efi'ect the decolorization. It is also desirable that the air and steam be controlled so that anoxidizing atmosphere be present in the kiln. With such an atmosphere the conversion changes the iron into ferric chlorid which is more volatile than the ferrous chlorid which otherwise would be formed.

If desired other compounds may be used than calcium chlorid. It is only necessary that calcium chlorid be produced at some stage in the manufacture of cement. For example I may usechlorid of lime. 'ljhe temperature required for the decompos1t1on. of. calcium chlorid is from"900 to 12QO O. but as cement manufacture requires higher temperatures it is' necessary that the substances at the end of the reaction be submitted to a temperature of from 1400 to 1500 C.

If desired I may replace coal and steam with water gas and air.

'Ifhe use of steam is necessary when it is desired to employ the ordinary raw material for the production of the cement and when white cement 1s required, but in the cases obtain a slightly colored cement, it is possible to employ the known reaction of I chlorid of lime u on potassic feld ar, but this reaction wi be effected accor mg to the present invention with new conditions and in an original man-- ner.

It has been found that the action of the mixture oflime and calciumchlorid upon temperature of orthoclase at the very hi 1400-1 500 not only al owe the com lets extraction of the potash from a fel spar (prthoclase) in the form of volatile otassium chlorid but also' allows the simultaneous production of 9. Portland cement of a hlg h y satisfactory composition and quality.

he reaction is efie'cted by means of a progressive heating u to 14001500 of an 1nt1m ate mixture, 0 a natural silicate of alumina and potas (and particularly of the feldspar orthoclase) with a suitable proportion of lime, and calcium chlorid in uantity suificlent or somewhat 'in excess of t at necessary to transform the potash of calcium chlorid,'heating H gressively up to 1400-1500 C. and subthe silicate into chlorid according to the reaction:

which at the. temperature of 1400 is eifected in a complete manner.

If the proportions of orthoclase, carbonate of lime, calcium chlorid are properly determinated the potash is entirely volatilized in the form of chlorid which is recovered by the usual methods employed in such cases (condensing chambers sprays, etc.) and the residue gives a Portland cement, all of whose elements arefound to be completely combined and in the same proportions as in the best qualities of cement, as it is easy to see from the composition of orthoclase.

. For example, the following materials will be progressively heated to 14001500 C. in a blast of air:

Orthoclase 36 parts, Carbonate of lime parts, -Calcium chlorid 10 parts,

together with a suflicient quantity of coal in a rotary furnace.

In previous rocesses attempts have not been made to ohtain a complete abstraction of all the potash from the feldspar, and such previous processes did not produce a product which could be utilized in the manufacture of cement. On the contrary by means of the present process the whole of the potash contained in the feldspar is liberated in the form of KCl; the cement thus produced is ractically free of combined alkali and it is own that a quantity of 1% of alkali renders the cement useless.

The orthoclase, carbonate of lime, and coal, will be chosen as pure as possible in order to obtain a cement of a minimum coloration.

It will be understood that the term ferrugineous raw materials as used in the claims refers to raw materials such as used -in cement manufacture which contain iron for example common clay containing considerable quantities of oxid 'of iron.

What I claim is:

1. A process for manufacturing white Portland cement by mixing the ordina ferrugineous raw materials of cement an the mixture promitting the mixture during the heating to the action of superheated steam, thereby volatilizing the metallic chlorids and collecting the white cement produced.

2. A rocess for manufacturing white Portlan cement by "mixing the ordinary ferrugineous'raw materials of cement and calcium chlorid, heating the mixture progressivelv in an oxidizing atmosphere up to 1400-1500 C. and submitting the mixture during the heating to the action of superheated steam, thereb volatilizing the metallic chloride and col ecting the White cement produced.

3. A process for manufacturing white Portland cement by mixing the ordinary ferrugineous raw materials of cement and calcium chlorid by mixing ferrugineous clay, lime and calcium chlorid, heating the mixture progressively up to 1 L0O-1500 C. and submitting the mixture during the heating to the action of superheated steam, thereby volatilizing the metallic chloride and collecting the white cement produced.

4:. A process for manufacturing white Portland cement by mixing the ordinary ferrugineous raw materials of cement, calcium chlorid and fuel. heating the mixture progressively up to 1400-1500 O. and submitting the mixture during the heating to the action of superheated steam, thereby volatilizing the metallic chloride and collecting the white cement produced.

5. A process for manufacturing white Portland cement by mixing ferrugineons clay, lime, calcium chlorid and coal, heating the mixture progressively up to 1400-1500 C. and submitting the mixture during the I Portland cement by mixing ferrugineous clay and calcium chlorid, then heating the mixture progressively in a blast of air up to 14001500 C. and submitting the mixture during the heating to the action of superheated steam, thereby volatilizing the metallic chloride and collecting the white cement produced.

In testimony whereof I affix my signature in presence of two Witnesses.

ANDRE HELBRONNER.

Witnesses:

Hanson G. CoxE, JOHN BAKER.

Correction in Letters Patent No. 1,239,912

II is hnrr-hy certified 1m: m Lmtws Patent No. 1,239,012, grnntrvl Septemhrr I 1.

H IT. u mn rluapplimx; uh Hf :hulr Holhrmuwr. of Paris. France, for an impl'nvvnn-nt in "'Ihv .\'|au|ufau1ture u! (mm-m," an error appears in the printnd specification requiring orrmtion as follows: Page 1, line H1, for the word "Arlother" rend Any; uml that the said Letters Patent should be real! with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 20th day of Now mber, A. 1)., 1917.

Isuzu) R. F. WHITEHEAD,

Arling Uommixxloner of Patents. 

